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The results obtained from the threshold tonal audiometry, revealed that in both groups, in the frequencies of 0.5, 1 and 2 kHz the auditory thresholds were present in values below 30 dB; therefore within the normal levels, bilaterally in most of the cases. While in the frequency range between 3 and 8 kHz, we observed a higher incidence of hearing loss at different levels. When this value is compared between the groups, we can see a worsening in the auditory thresholds in the large majority of frequencies between 3 and 8 kHz, for group I. This worsening in the hearing loss was significant in the frequencies of 3 kHz (left ear) and 4 kHz (bilaterally). And finally, we did the analyses and classified the audiometries6. Thus, we noticed that in the right ear of Group I, 16 (40%) individuals were classified as normal, 20 (50%) had level 1 hearing loss and 4 (10%) had level 2 loss. While in the left ear of this same Group 12 (30%).
DISCUSSION
The present study, the most frequent complaints from Group I were tinnitus, allergy and recruitment; and for Group II they were: tinnitus, recruitment and auto-phonia. In both groups, we have the two complaints most frequently reported by the National Committee of Noise and Auditory Preservation. Nonetheless, we have to stress the presence of the complaint of allergy in Group I, which can be associated with the contact with the pesticide. The analysis of the immittance measures showed a predominance of type A curves, which matched the sensorineural profile of the noise induced hearing loss. Even in the few cases with type Ad curve, we did not see any conduction problem in the audiometry. In the present study, we see that in both groups the audiometries showed a hearing loss in the high frequencies, with peaks at 4 and 6 kHz, as it is commonly seen in audiometries from patients with NIHL. This configuration showed that the lesion caused by the noise exposure and/ or pesticides reach a particular region of the cochlear baal turn. Other authors also reported a predominance of hearing loss in the high frequencies.In a quantitative analysis of the tonal threshold audiometry, a statistically significant difference was seen between the groups, with a worsening of the thresholds for group I, in the frequency of 3 kHz, in the left ear and in the frequency of 4 kHz, bilaterally. In classifying the audiometries, we noticed that in Group I, more than 60% of the individuals have NIHL, while in Group II, this figure drops to 42.5%, in other words, the group with concurrent exposure to noise and pesticide presented a higher incidence of hearing loss, according to this classification. Thus showing that both elements, working together, worsen the hearing loss. Therefore, the present study is in agreement with other scholars who discussed the interaction of noise and chemicals and found more pronounced hearing loss in those individuals exposed to both elements.
CONCLUSION
After analyzing the audiological findings and com-paring Groups I and II, we conclude that the workers exposed to occupational noise and pesticide are under a higher risk of developing hearing loss when compared to those workers exposed to noise only. Thus, it is important that Hearing Protection Programs also consider these fac-tors so as to better prevent the damages caused by these noxious elements.
REFERENCES
1. Brasil. Ministério do Trabalho e Emprego. Portaria 3.214 de 8 de junho de 1978. Normas regulamentadoras de segurança e saúde no trabalho (NR-15): atividades e operações insalubres. Brasília, 1978. Disponível em http://www.tem.gov.br/legislacao/normas_regulamentadoras/ nr_15.pdf. Acessado em 10 de junho de 2007.
2. Ferreira JM. Perda auditiva induzida por ruído. Bom Senso e Con-senso. São Paulo. ed. VK; 1998.
3. Comitê Nacional de Ruído e Conservação Auditiva. Perda auditiva induzida pelo ruído relacionado ao trabalho. Acust Vibr. 1994; 13:123-5.
4. Barregard L, Axelsson A. Is there an ototraumatic interaction between noise and solvents? Scand Audiol. 1984;13:151-5.
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